Antitumoral and antiangiogenic activity of Portuguese propolis in in vitro and in vivo models

Propolis, a natural product, has important biological properties, however, studies with Portuguese propolis are scarce. Thus, we aimed to characterize the chemical composition and the antitumoural and antiangiogenic activities of a sample from Pereiro (Portugal). The chemical profile of our propolis sample (P10.EE) is similar to the poplar propolis type. P10.EE decreased cell viability of different tumour cells, being less cytotoxic against non-tumoural cells. P10.EE decreased MDA-MB-231 and DU145 cell proliferation and migration, with cell cycle changes and increased cell death. The increased glucose consumption and lactate production in MDA-MB-231 cells is explained by an increased expression of different metabolism-related proteins. P10.EE induced a decrease in HBMEC cells total biomass and proliferation and decreased vessel sprouting in the chicken chorioallantoic membrane. Additionally, P10.EE potentiates paclitaxel effect in MDA-MB-231 and DU145 cells. Concluding, P10.EE can be a good candidate for cancer drug development since it affects different characteristics that dictate tumorigenesis.This work was supported by the Life and Health Sciences Research Institute, University of Minho, Portugal, and Fundacao para a Ciencia e Tecnologia (FCT) (SFRH/BD/5199712012 to V.M.G.), through Fundo Europeu de Desenvolvimento Regional-QREN-COMPETE, projects PTDC/AAC-CLI1098308/2008 and PTDC/AAC-CLI/11809212010 and also CERNAS (project PEst-OE/AGR/UI0681/2011)

Self-aggregation of free base porphyrins in aqueous solution and in DMPC vesicles

Free base porphyrin (PPhe), derivatized with aminosulfonyl groups linked to the aromatic amino acid phenylalanine at the meso-positions, was mixed with DMPC vesicles. The resulting interaction was studied by absorption, steady-state and transient state fluorescence, at different pHs.http://www.sciencedirect.com/science/article/B6TFB-4R68NKV-2/1/aca6e255f297903981898ccea264a38

Effect of different electrolytes on the swelling properties of calyx[4]pyrrole-containing polyacrylamide membranes

Calix[4]pyrrole (1) was synthesized and characterized and this macrocycle was incorporated in polyacrylamide gels. The presence of meso-octamethyl-porphyrinogen inside of gel was checked using infrared spectroscopy, differential scanning calorimetry, and swelling studies. The swelling degree of these hydrogels in equilibrium with different electrolytes (NaCl, LiCl, KCl, CaCl2 and AlCl3) was measured in a concentration range 0.1-0.5 mol dm-3. Although no significant alterations in the swelling degree can be found for the different 1:1 electrolytes, when the cation charge of unsymmetrical electrolytes increases, the gel swells in a significant way. This swelling process is enhanced by the presence of calyx[4]pyrrole. The effect of alkaline hydrolysis of polaycrylamide-based hydrogels was also studied. The hydrolysed hydrogels collapse in the presence of the electrolytes; this behavior is dependent on the hydrolysis degree, electrolyte charge and calyx[4]pyrrole presence and concentration; the latter leads to polyacrylamide with tailor-made properties.http://www.sciencedirect.com/science/article/B6TWW-4K0FJT9-2/1/a2e10fed9f08e8248532610bc3e2bdc

Self-association of free base porphyrins with aminoacid substituents in AOT reverse micelles

The aggregation properties of aminosulfonyl porphyrins with aminoacid substituents: methionine with the acid function methylated, PMetCH3; phenylalanine, PPhe; attached to the para positions of the meso phenyls of the porphyrin, was followed in organic solvents, water-dioxane mixtures and in reverse micelles of aerosol OT (AOT RM), using absorption, steady-state and time-resolved fluorescence. In AOT RM in the absence of water, both porphyrins are mainly present as monomers with the Soret band around 420 nm and with emission maxima around 649 and 717 nm. In the presence of water accounted for by parameter [omega]0, [omega]0 = [H2O]/[AOT], the solubility of both porphyrins is enhanced and followed by important spectral changes similar to those observed in the solvent mixtures: new maxima in absorption around 405 nm and in emission around 670 nm. A concomitant increase of the aggregates' contribution is found for PMetCH3, whereas for PPhe the effect is much more pronounced until [omega]0 = 10, above which a de-aggregation process occurs, due to competition between intra- and inter-molecular interactions. The small resonant light scattering signals observed points to the existence of aggregates of small dimensions whose nature is discussed in terms of exciton theory.http://www.sciencedirect.com/science/article/B6TGY-4HM7S0D-1/1/0b4fa2b44d0d626b2e1b99609a937ba

Mean distance of closest approach of ions: Lithium salts in aqueous solutions

Numerical values for the mean distance of closest approach of ions, "a", for lithium salts in aqueous solutions are presented and discussed. These values were obtained from both experimental activity and diffusion coefficients, and estimated by using different theoretical approaches.http://www.sciencedirect.com/science/article/B6TGR-4RR1NKM-1/1/b8d3cdac33991c5424d567940bc0c3a

Singlet and triplet energy transfer in a bichromophoric system with anthracene covalently linked through sulfonamide to a meso-tetraphenylporphyrin

A bichromophoric system in which anthracene has been covalently linked to meso-tetrakis(phenyl)porphyrin (TPP) moieties by alkylsulfonamide spacers has been synthesized and fully characterized. A spectroscopic and photophysical study of this system in dimethylformamide (DMF) has been undertaken to study electronic energy transfer between the anthracene and porphyrin units in excited singlet and triplet states. By use of steady-state and time-resolved fluorescence techniques as well as phosphorescence and laser flash phototolysis, it is shown that excitation to either the singlet or triplet states of the anthracene leads to energy transfer to the lower lying S1 and T1 states of TPP group. The efficiency and the rate of energy transfer have been determined. Although the estimated efficiency of the energy transfer process in the singlet manifold is high, the coexistence of fluorescence from both moieties when exciting the anthracene, together with observation of a biexponential decay of the porphyrin fluorescence when excited in the porphyrin Soret band suggest that communication exists between the two chromophores. This is discussed in terms of Förster type energy transfer and geminate radical pair mechanisms, possibly involving nonplanar (between chromophores) excited state geometry. In the flash photolysis studies, only the porphyrin triplet state was observed. The dominance of nonradiative deactivation in the overall decay of the excited singlet and triplet states is indicated.http://www.sciencedirect.com/science/article/B6TGY-4F8TKBN-1/1/5c1f57ef1c3195eb7c6546dfa4f427f